1. Field of the Invention
This invention is related to a switch means for stopping an operation of a stop watch with an electronic circuit, and to a memory system for storing data of a measured elapsed time.
2. Description of the Related Art
In already known stop watches or electronic watches having a stop-watch function, a mechanical contact point system operated by a push button or a stem is provided for starting or stopping the movement of the stop watch.
Further, in, for example, large athletic meetings, the time measurement of a race is stopped when a runner passes a certain point at which a light interruption system or light reflection system using, for example, photo electronic sensors, is located.
Recent technological developments, however, have led to the use of a signal generated from a piezo electric element when loaded with an impact force, as an input signal of the stop watch.
Such a piezo electric element switch is disclosed, for example, in Japanese Unexamined Patent Publication No. 53-80263, in which an electronic circuit of the watch is operated by an impact signal generated by striking a piezo electric element fixed on a portion of the watch.
In, for example, a ski competition, there is a demand for a portable stop-watch with which the competitors in a race or ordinary skiers can obtain an elapsed time without using the solid type time measurement instrument afore mentioned, and thus the system of stopping the stop watch with an impact signal would be convenient. However in, for example, a ski competition, obviously such a stop watch often would be unavoidably subjected to an impact force during a normal ski-race, etc., and thus a stop watch as mentioned above would not be suitable for such activities.
On the other hand, the skier often wants to store a plurality of elapsed time data or the stop time data in the memory, to compare present times with past times.
Heretofore, in a stop watch function of an electronic watch available on the market, a plurality of memories are provided in the watch for memorizing measured time data and for retrieving this data whenever required after a measurement operation to obtain an intermediate elapsed time, for example, a lap time at 5 km intervals in a marathon race. But there must be some limitation to the capacity of the memory circuit, and therefore, in a watch having a system for stopping the watch with an impact force, an elapsed time measuring operation will be carried out every time an impact force is felt by a skier on the arm and, therefore, only the most important one of actual elapsed time is memorized in the memory Accordingly, a problem arises in that only one data in the exercises can be retrieved for a downhill ski run, for example, because during the ski run practice, a skier runs several times on the same downhill course and the data obtained at each run is to be evaluated with the other data obtained thereby.
In view of the above problems, the object of this invention is to provide a switch of a stop-watch to be used to measure the time accurately during a competition such as a ski or bicycle race, by which the users must carry out a relatively complicated operation to stop the watch.
Another object of this invention is to provide a stop watch having a function for memorizing a plurality of only the most important elapsed time data in a plurality of merories and for retrieving this data thereafter, and further having a function for memorizing the number of data input and moreover, having a function for displaying this data as, for example, the elapsed time in xx minutes and yy seconds at a certain number of times the data was obtained.